// SPDX-License-Identifier: Apache-2.0
/* Copyright 2024 Huawei Technologies Co.,Ltd. All rights reserved. */

#include <string.h>
#include <stdint.h>
#include "crypto/sm4.h"

#define AES_BLOCK_SIZE	16
#define U32_BYTES	4
#define BYTE_TO_BIT	8
#define U32_BITS	32
#define FIRST_KEY_STEP	13
#define SECOND_KEY_STEP	23

#define FIRST_DATA_STEP		2
#define SECOND_DATA_STEP	10
#define THIRD_DATA_STEP		18
#define FOURTH_DATA_STEP	24
#define TOTAL_ROUND		36
#define F_ROUND			32
#define BUF_LEN			128

const __u32 TBL_SYS_PARAMS[4] = {
	0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
};

const __u32 TBL_FIX_PARAMS[32] = {
	0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
	0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
	0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
	0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
	0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
	0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
	0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
	0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
};

const __u8 TBL_SBOX[256] = {
	0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7,
	0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
	0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3,
	0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
	0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a,
	0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
	0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95,
	0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
	0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba,
	0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
	0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b,
	0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
	0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2,
	0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
	0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52,
	0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
	0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5,
	0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
	0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
	0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
	0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60,
	0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
	0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f,
	0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
	0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f,
	0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
	0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd,
	0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
	0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e,
	0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
	0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20,
	0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
};

static void get_u32(__u8 *in, __u32 *out)
{
	__u32 i = 0;

	*out = 0;
	for (i = 0; i < U32_BYTES; i++)
		*out = ((__u32)in[i] << ((U32_BYTES - 1 - i) * BYTE_TO_BIT)) ^ *out;
}

static void put_u32(__u32 in, __u8 *out)
{
	__u32 i = 0;

	for (i = 0; i < U32_BYTES; i++)
		*(out + i) = (__u32)(in >> ((U32_BYTES - 1 - i) * BYTE_TO_BIT));
}

static __u32 move(__u32 data, __u32 length)
{
	__u32 result = 0;

	result = (data << length) ^ (data >> (U32_BITS - length));

	return result;
}

static __u32 func_key(__u32 input)
{
	__u8 ucSboxValueList[U32_BYTES] = { 0 };
	__u8 ucIndexList[U32_BYTES] = { 0 };
	__u32 i, ulTmp;

	put_u32(input, ucIndexList);
	for (i = 0; i < U32_BYTES; i++)
		ucSboxValueList[i] = TBL_SBOX[ucIndexList[i]];

	get_u32(ucSboxValueList, &ulTmp);
	ulTmp = ulTmp ^ move(ulTmp, FIRST_KEY_STEP) ^
		move(ulTmp, SECOND_KEY_STEP);

	return ulTmp;
}

static __u32 func_data(__u32 input)
{
	__u8 ucSboxValueList[4] = { 0 };
	__u8 ucIndexList[4] = { 0 };
	__u32 i, ulTmp;

	put_u32(input, ucIndexList);
	for (i = 0; i < U32_BYTES; i++)
		ucSboxValueList[i] = TBL_SBOX[ucIndexList[i]];

	get_u32(ucSboxValueList, &ulTmp);
	ulTmp = ulTmp ^ move(ulTmp, FIRST_DATA_STEP) ^
		move(ulTmp, SECOND_DATA_STEP) ^
		move(ulTmp, THIRD_DATA_STEP) ^
		move(ulTmp, FOURTH_DATA_STEP);

	return ulTmp;
}

void sm4_encrypt(__u8 *key, __u32 key_len, __u8 *input, __u8 *output)
{
	__u32 tmp_keys[U32_BYTES] = { 0 };
	__u32 keys[TOTAL_ROUND] = { 0 };
	__u32 data[TOTAL_ROUND] = { 0 };
	__u32 i, j, k, in_len;
	__u8 p[BUF_LEN];

	if (key_len < AES_BLOCK_SIZE)
		return;

	for (i = 0; i < U32_BYTES; i++) {
		get_u32(key + U32_BYTES * i, &tmp_keys[i]);
		keys[i] = tmp_keys[i] ^ TBL_SYS_PARAMS[i];
	}

	for (i = 0; i < F_ROUND; i++)
		keys[i + 0x4] = keys[i] ^ func_key(keys[i + 0x1] ^ keys[i + 0x2] ^
						   keys[i + 0x3] ^ TBL_FIX_PARAMS[i]);

	in_len = AES_BLOCK_SIZE;
	for (i = 0; i < in_len; i++)
		*(p + i) = *(input + i);

	k = AES_BLOCK_SIZE - (in_len % AES_BLOCK_SIZE);
	for (i = 0; i < k; i++)
		*(p + in_len + i) = 0;

	k = in_len / AES_BLOCK_SIZE + ((in_len % AES_BLOCK_SIZE) ? 1 : 0);
	for (j = 0; j < k; j++) {
		for (i = 0; i < TOTAL_ROUND - F_ROUND; i++)
			get_u32(p + AES_BLOCK_SIZE * j + U32_BYTES * i, &data[i]);

		for (i = 0; i < F_ROUND; i++)
			data[i + 0x4] = data[i] ^ func_data(data[i + 0x1] ^ data[i + 0x2] ^
							     data[i + 0x3] ^ keys[i + 0x4]);

		for (i = 0; i < TOTAL_ROUND - F_ROUND; i++)
			put_u32(data[TOTAL_ROUND - i - 1],
				output + AES_BLOCK_SIZE * j + U32_BYTES * i);
	}
}
